Abstract:

The invention relates to a supply device (32) for sewing material layers
(16, 18, 20) of a large area sewing product such as mattress panels for
example, comprising several sewing material layers (16, 18, 20),
particularly at least three, preferably one sewing material layer of
elastic material, for example foamed material, and one sewing material
layer intended as a top layer, which layers are to be stitched together
using a sewing machine (14) with at least one sewing unit, in particular
a multiple-needle sewing machine, wherein said supply device consists of
at least one roll receiver (34) capable of receiving at least two
material rolls (24, 26, 28, 36, 38, 40), each material roll (24, 26, 28,
36, 38, 40) being rotatably supported in a holder (42) of the roll
receiver (34), and wherein sewing material layers (16, 18, 20) can be
removed from the material rolls (24, 26, 28, 36, 38, 40) arranged in a
roll receiver (34) and fed to the sewing unit, wherein the sewing
material layers (16, 18, 20) from a roll receiver (34) can be
alternatively fed to the sewing unit.

Claims:

1.-28. (canceled)

29. A supply device for a sewing machine, particularly a multiple-needle
sewing machine, with at least one sewing unit, for sewing material layers
of a large-scale sewing product such as mattress panels for example,
comprising several sewing material layers, particularly at least three,
preferably having one sewing material layer of elastic material, for
example foamed material, and one sewing material layer intended as a top
layer, which layers are to be stitched together using the sewing machine,
said supply device comprising:at least two material rolls;at least one
roll receiver capable of receiving the material rolls;a holder being
arranged at the roll receiver, wherein each material roll is rotatably
supported in a holder of the roll receiver;means for removing the
material layers from the material rolls arranged in the roll receiver,
and for feeding the material layers to the sewing unit; andwherein the
sewing material layers can be alternatively fed to the sewing unit from
the roll receiver.

30. The supply device according to claim 29, wherein each material roll is
rotatably supported in the holder.

31. The supply device according to claim 29, wherein the holders of the
roll receiver are arranged substantially horizontally adjacent to each
other or vertically above each other.

32. The supply device according to claim 29, wherein material is stored or
storable in the holders of the roll receiver which is identical or which
is at least similar with regard to the properties essential for the
sewing process.

33. The supply device according to claim 29, wherein each holder includes
at least two spaced cantilever arms and a pivot for receiving the
material roll extending between the cantilever arms.

34. The supply device according to claim 29, wherein the holder is
designed in a trough-like fashion in such a way that it can be adapted to
the outer contour of the material roll.

35. The supply device according to claim 34, wherein the holder includes a
friction-reducing surface facing the material roll.

36. The supply device according to claim 34, wherein the holder includes
several, at least two, rollers which are rotatably supported in the
holder an on which the material roll can be placed.

37. The supply device according to claim 29, wherein several, at least
two, roll receivers for respectively receiving at least two material
rolls are arranged adjacently to each other in a substantially horizontal
plane in such a manner that the pivots of the material rolls are aligned
substantially parallel to each other.

38. The supply device according to claim 29, wherein at least the upper
holder of the roll receiver includes a receiving assembly by which the
material roll can be conveyed to the upper holder.

39. The supply device according to claim 38, wherein the receiving
assembly includes a carriage having a supporting surface which can be
applied at least partly against the material roll and being movable
relative to the holder between a retracted and an extended position and
being bendable relative to the holder in an end position that corresponds
to the extended position.

40. The supply device according to claim 39, wherein the carriage is
substantially L-shaped in the longitudinal section, and wherein a leg
forms a supporting structure supporting the material roll.

41. The supply device according to claim 39, wherein the supporting
surface consists of several rollers or cylinders rotatably supported in
the carriage.

42. The supply device according to claim 39, wherein an energy storing
device and/or a linear motor are arranged between the carriage and the
receiving assembly.

43. The supply device according to claim 42, wherein the linear motor is
designed as a hydraulic or pneumatic cylinder and/or that the energy
storing device is designed as a tension spring that can be stretched upon
a movement of the carriage from the retracted to the extended position.

44. The supply device according to claim 39, wherein the roll receiver
includes a supporting frame on which the respective holders are formed as
two cantilever arms arranged with a distance in the supporting frame and
between which the material roll can be supported for rotation, wherein a
rod or cylinder can be placed in the cantilever arms, said rod or
cylinder centrically passing through the material roll.

45. The supply device according to claim 44, wherein at least one
cantilever arm of each holder is designed in such a manner that it can be
displaced relative to the supporting frame, preferably pivoted about an
axis extending parallel to the rod or cylinder and/or about a
perpendicular axis, and/or in such a manner that it can be demounted.

46. The supply device according to claim 39, wherein at least two holders
of the roll receiver are associated with a respective connecting and
guiding assembly for the sewing material layers to be removed from the
material rolls is associated with.

47. The supply device according to claim 46, wherein the connecting and
guiding assembly includes two mutually spaced clamping devices by which
at least one sewing material layer can be fixed by clamping.

48. The supply device according to claim 47, wherein each clamping device
includes at least one cylinder which can be pivoted relative to the
sewing material layer.

49. A process for feeding a sewing material layer to a sewing machine,
particularly a multiple-needle sewing machine, the process
comprising:providing a supply device having a roll receiver, the roll
receiver having at least two holders, namely, a first holder and a second
holder;arranging at least two material rolls, e.g. a first material roll
and a second material, wherein one material roll is arranged at each of
the holders;providing at least two sewing material layers, preferably at
least a first sewing material layer of elastic material, for example
foamed material, and a second top layer of large-scale sewing products
such as, for example, mattress panels;providing each of the material
rolls with one of the sewing material layers, particularly, the first
material roll is provided with the first sewing material layer, and the
second material roll is provided with the second sewing material layer,
wherein the second sewing material layer arranged adjacent to, above or
below the first sewing material layer;removing the sewing material layers
from the material rolls of the holder of the roll receiver;feeding the at
least two sewing material layers from the supply device to a sewing unit
of the sewing machine;stitching together the sewing material layers by
the sewing unit;wherein the second sewing material layer can be removed
if necessary from the second material roll in the second holder of the
roll receiver and fed to the sewing machine.

50. The process according to claim 49, wherein the second sewing material
layer is connected with the end of the first sewing material layer.

51. The process according to claim 50, wherein the first sewing material
layer, prior to its connection with the second sewing material layer, is
separated, particularly cut, into two sections substantially at right
angles to its longitudinal extension.

52. The process according to claim 50, wherein the ends to be connected
with each other are butted up against each other and are connected with
each other using at least one adhesive tape which overlaps both ends.

53. The process according to claim 50, wherein the ends to be connected
with each other are arranged in an overlapping fashion one on top of the
other and are connected with each other using at least one connecting
element, for example, a plastic thread penetrating through both ends.

54. The process according to claim 49, wherein the sewing material layers
are stored in the form of material rolls above each other and/or adjacent
to each other in the roll receiver.

55. The process according to claim 49, wherein, in the holders of a roll
receiver, material is stored which is substantially identical or at least
similar with regard to the properties essential for the sewing process.

56. The process according to claim 50, wherein the sewing material layers
to be connected with each other are fixed in their position relative to
each other prior to connecting their ends.

Description:

[0001]The present invention relates to a supply device for layers of
sewing material of a large area sewing product such as mattress panels
for instance, comprising several layers of sewing material, preferably at
least two layers, one preferably of elastic material, for instance foamed
material, and one as a top layer, which layers are to be stitched
together using a sewing machine with at least one sewing unit,
particularly a multiple-needle sewing machine, said supply device
comprising at least one roll receiver capable of receiving at least two
material rolls. The invention also relates to a process for feeding a
layer of sewing material from a supply device to a sewing machine with at
least one sewing unit, preferably a multiple-needle sewing machine, in
which preferably at least two layers of sewing material, which preferably
comprise at least one layer of elastic material, for instance foamed
material, and one top layer, of large area sewing products such as
mattress panels for instance, are stitched together, wherein two material
rolls with layers of sewing material are arranged in two holders of a
roll receiver in the supply device and a first layer of sewing material
is removed from one holder of the roll receiver and fed to the sewing
machine.

[0002]Devices and processes of this type are known per se in prior art.
Such supply devices serve to provide the sewing material to be sewn up
and especially individual layers of sewing material for their processing
by the sewing unit. The sewing unit may comprise a sewing material
support with a presser foot arranged above the sewing material support
and a needle bar in which a plurality of needles are arranged. Below the
sewing material support which is designed as a perforated plate, the
sewing unit includes a number of gripper hooks are attached to a rod
which correspond to the number of needles. The gripper hooks and needles
are moved in an oscillating manner for forming chain stitches or double
chain stitches or the like in the material which is supported on the
sewing material support. The sewing material is provided by the supply
device, for instance by unrolling the sewing material from a material
roll. A separate material roll is provided for each layer of sewing
material.

[0003]A supply device of this type is disclosed for example in DE 203 17
988 U1, in which material rolls in a number corresponding to the number
of layers of sewing material are horizontally arranged one behind the
other. For each material roll a guiding assembly is arranged in a frame,
and the respective material roll of the sewing material support can be
placed in the guiding assembly. Such a guiding assembly allows the
material roll being placed by its lateral area on a conveyor belt.

[0004]Vertically above each material roll a further material roll is
provided using a lifting device, so that the lower material roll can be
replaced by lowering the material roll arranged above the lower material
roll as soon as the material of the lower material roll has been
completely exhausted or needs to be changed.

[0005]Even though this supply device offers advantages concerning the
setup time and the manual handling of the actually heavy material rolls,
it does not yet constitute a satisfying solution considering the time
which is still required for changing the layers of sewing material within
different batches.

[0006]There are also known processes for sewing a material which
particularly comprises at least two preferably large area layers of
sewing material using an upper thread and a lower thread. Such processes
are performed for instance in backstitch and preferably in double
backstitch sewing machines, wherein a needle with the upper thread
stitches into the sewing material and the upper thread is connected with
the lower thread. To this end, a gripper hook with the lower thread
engages a loop which is formed by the upper thread during the retraction
of the needle, whereupon the connection between the upper thread and the
lower thread is produced. At the beginning of the seam and after cutting
the upper thread and the lower thread at the end of the seam, thread ends
are produced in the region of both surfaces of the sewing material which
are usually cut by hand. This is time-consuming and may also involve the
risk of damaging the sewing material at the time of cutting the thread
ends.

[0007]On part of the device, it is an object of the present invention to
further develop a supply device and a process for feeding a layer of
sewing material from a supply device to the effect that the handling can
be facilitated and the setup time be reduced.

[0008]As a solution of this object the invention proposes a supply device
in which each material roll is rotatably supported in a holder of the
roll receiver and layers of sewing material can be removed from the
material rolls arranged in a roll receiver and fed to the sewing unit,
wherein the layers of sewing material from one roll receiver can be fed
alternatively to the sewing unit.

[0009]By the fact that each material roll is rotatably supported in a
holder of the roll receiver, layers of sewing material can be provided
not only by the material rolls which are active in a sewing operation,
but the layers of sewing material of the available material rolls can be
combined in any desired manner. Accordingly, if a material roll is
exhausted, the beginning of the sewing material layer of an assigned
material roll can be tacked to the end of the sewing material layer of an
exhausted material roll, thus quasi achieving a continuous sewing
process. Setup time is merely required for the short period of switching
the supply of the sewing material layer from the one material roll to the
other. The sewing material layers which are tacked to each other may also
vary from each other if for instance a different sewing product shall be
produced by the sewing unit. It is possible in this way to achieve high
flexibility and a short setup time. The supply device according to the
invention is particularly beneficial with regard to an increasing number
of sewing material layers, because the supply device according to the
invention considerably reduces the setup time. The fact that sewing
material layers can be alternatively fed from a roll receiver provides
for high flexibility in the production of sewing products by the sewing
unit.

[0010]Advantageously, each material roll is rotatably supported in a
holder. Thus each material roll can be integrated in the manufacturing
process of the sewing product in quasi any order. Time-consuming manual
operations such as exchanging the material rolls or the like are not
required. The holder allows a material roll supported by the holder being
easily exchanged if needed. The holder allows easier and faster provision
of a sewing material layer of a material roll. Preferably, the holder is
a component part of the roll receiver. The roll receiver may be
constituted for instance by a frame in which one or more holders can be
inserted or retracted. The holder may comprise means suitable for holding
the material roll in the desired position. Supporting the material roll
for rotation can be implemented for instance by rotatable cylinders on
the holder, on which cylinders the material roll is placed. Moreover, the
material roll may be coaxially connected to a rotatable shaft which is
provided on the holder, thus ensuring rotation of the material roll. The
holder itself may be articulated with respect to the roll receiver, so
that it can be pivoted with respect to the roll receiver. Moreover, the
holder may be designed as a carriage which is movable preferably
horizontally with respect to the roll receiver, thus enabling a material
roll being moved out of or into the roll receiver. It can be provided for
the holders of the roll receiver being arranged substantially
horizontally one beside the other or vertically one above the other, thus
allowing easy connection of the sewing material layers to be connected
with each other.

[0011]It may be provided for the sewing material layers of neighboring
material rolls to be connected with each other. Thus the new sewing
material layer can be introduced in the manufacturing process
substantially automatically through the previous sewing material layer.

[0012]The invention further proposes that material which is substantially
identical or which is similar at least with regard to the properties
essential for the sewing operation can be or is supported in the holders
of a roll receiver. This allows the production of huge amounts of a
sewing product, especially of a large area sewing product while
simultaneously achieving a high sewing rate of the sewing unit due to the
short setup time. Hence, the production speed is determined mainly by the
speed of the sewing unit.

[0013]In a further development, each holder includes at least two spaced
cantilever arms and a pivot for receiving a material roll extending
between the cantilever arms. In this way, the material roll can be easily
supported for rotation on the holder. For mounting purposes it may be
provided that at least one of the cantilever arms is arranged for
pivoting on the holder. This allows easy insertion of the material roll
in the holder and its connection with the pivot, for instance by placing
the material roll in the holder, inserting the pivot through the material
roll and putting the pivot in a position to support the material roll for
rotation by a pivoting movement of the cantilever arms. The cantilever
arm can thus be pivoted away from the region which is used for removing
the material roll from or inserting the material roll in the holder.

[0014]The holder may be trough-like with an approximately semicircular
cross section and it can be adapted to the outer contour of the material
roll. This design is particularly suitable in a case where the material
roll is not supported on the holder via a pivot. In this design, the
material roll outer contour rolls off against the holder during the
removal action of the sewing material layer. A constructionally simple
and reliable design of the holder can be achieved. Moving parts can be
avoided. For further improving the reliability of the bearing, the holder
can be preferably adapted to the outer contour of the material roll.

[0015]Furthermore, it may be provided for the holder to include a
friction-reducing surface which faces the material roll. This allows on
the one hand to reduce driving energy for removing a sewing material
layer and on the other hand to reduce influences especially on the sewing
material layer caused by removing the sewing material layer from the
material roll. The friction-reducing surface may be formed for instance
by a polished or chromed steel surface, thus avoiding inadmissibly high
pulling forces on the sewing material layers.

[0016]A further embodiment of the holder may provide for the holder to
have several rollers, namely two at least, which are supported for
rotation in the holder and on which the material roll can be placed, thus
achieving a simple bearing of the material roll at a low friction. This
embodiment is particularly beneficial because the sewing material layer
is not subject to mechanical stresses, except of the forces occurring at
the time of removing a sewing material layer. This is particularly
beneficial especially in the case of delicate sewing material layers.

[0017]A further development provides that several receivers, namely two at
least, for respectively receiving at least two material rolls are
arranged next to each other in a substantially horizontal plane
preferably in such a way that the pivots of the material rolls are
substantially aligned parallel to each other. By this parallel alignment
the individual sewing material layers of the material rolls can be fed to
the sewing unit in a simple manner, without requiring complicated
alignments of the respective sewing material layers to each other. This
reduces stresses on the sewing material layers during the processing.
Moreover, the alignment in a substantially horizontal plane also allows
the sewing material layers, particularly in large area sewing material,
to be substantially uniformly stressed in the transverse direction. This
is also beneficial for the processing by the sewing unit, because the
individual sewing material layers can be fed at a substantially
homogeneous tension. Troubles like crimping or the like in large area
sewing material can be mostly avoided.

[0018]At least the upper holder of a roll receiver may include a receiving
assembly by which the material roll can be conveyed to the upper holder.
In this way, material rolls which are partly as heavy as 50 kg or more
can be handled more easily. Manoeuvring the material rolls to the upper
holder with high manual efforts is no longer required. The material roll
may instead be inserted in the receiving assembly and conveyed at least
partly automatically to the intended position in the holder. This also
saves time.

[0019]A further development provides for the receiving assembly to include
a carriage having a supporting surface that can be at least partially
applied against the material roll, the carriage being movable between a
retracted and an extended position relative to the holder and bendable
relative to the holder in an end position that corresponds to the
extended position. Thus the material roll can be securely guided during
loading the holder and it can be easily inserted in the holder. In
addition, this embodiment is particularly suited at least for partial
automation, so that the material roll can be inserted in the holder
mainly without a manual action.

[0020]In the longitudinal section, the carriage may be designed
substantially L-shaped and may form a leg against which the material roll
can be supported, so that in the bent end position relative to the holder
a supporting structure can be formed for the material roll that is
supported against the leg due to its weight. The material roll is thus
securely supported against tilting with respect to the carriage. Combined
with bending, a supply device can be provided which allows easy loading
of a holder with a material roll.

[0021]The supporting surface can also be formed by several rollers or
cylinders which are supported for rotation in the carriage. This allows
easy axial positioning of the material roll in the retracted state of the
carriage.

[0022]Between the carriage and the receiving assembly an energy storing
device and/or a linear motor can be arranged. The energy storing device
and/or the linear motor may provide for the holder with the material roll
being movable to the intended position of the roll receiver substantially
by pulling. Manual actions can thus be avoided to a large extent.
Moreover, automation of the loading operation can thus be achieved. The
linear motor may be designed as a hydraulic or pneumatic cylinder and/or
the energy storing device may be designed as a tension spring capable of
stretching upon movement of the carriage from the retracted to the
extended position.

[0023]A further development provides for the roll receiver to have a
supporting frame on which the holders are each formed as two cantilever
arms arranged with a distance on the supporting frame. A material roll is
rotatably supported between these cantilever arms, and a rod or cylinder
which centrically passes through the material roll can be placed in the
cantilever arms. This embodiment works in a case for instance in which
the material roll shall be transferred to the holder using a lifting
device such as fork lift. The material roll can thus be placed in the
holder in which it is first supported on a base of the holder. To support
the material roll for rotation, the rod or cylinder is now centrically
inserted through the material roll and then placed in the cantilever arms
thus achieving a rotatable bearing arrangement of the material roll.
Advantageously, it is sufficient for this purpose to lift the material
roll a short distance, thus achieving easy handling. The arrangement of
the holder simultaneously provides for safe handling, so that dangerous
situations such as slippage of the material roll or the like caused by
assembly faults can be avoided.

[0024]The invention further proposes that at least one cantilever arm of
each holder is designed in such a manner that it can be moved relative to
the supporting frame, preferably pivoted about an axis extending parallel
to the rod or cylinder and/or about a perpendicular axis, and/or in such
a manner that it can be demounted. This additionally simplifies the
mounting of the material roll on the holder, for instance by moving the
cantilever arm for mounting purposes in such a manner that the cantilever
arm releases the material roll laterally. The material roll can then be
removed from the holder. Vice versa, for setup purposes, the material
roll can be inserted in the holder and the rod or cylinder centrically
inserted in the material roll and the material roll moved to the desired
position with respect to the holder by returning the cantilever arm, thus
ensuring the rotatable support of the material roll. Preferably, the
cantilever arm may include a drive which simultaneously serves to lift
the material roll with respect to the holder, if necessary.

[0025]A further embodiment provides that a connecting and guiding assembly
for the sewing material layers to be removed from the material rolls is
associated with at least two holders of a roll receiver. It is possible
through the connecting and guiding assembly to hold a sewing material
layer of a material roll ready for the connection with one end of a
different sewing material layer that is currently not involved in the
manufacturing process. This embodiment is suited among others for
switching between sewing material layers for instance in a case where
different sewing material layers are arranged on the material rolls of
the two respective holders. But it is also possible to easily achieve the
continuation of the manufacturing process with a sewing material layer
that is removed from one material roll by coupling the end of this sewing
material layer to the beginning of the next sewing material layer. To
this end, the connecting and guiding assembly can connect the end of one
sewing material layer with the beginning of the other sewing material
layer.

[0026]The connecting and guiding assembly may comprise two mutually spaced
clamping devices enabling at least one sewing material layer to be fixed
by clamping. This embodiment enables the beginning of a sewing material
layer being held ready for a quick connection. The clamping device
further enables the two ends that are to be connected to be fixed in a
predetermined position, thus achieving easy connection of the two ends.

[0027]Each clamping device may further include at least one cylinder that
can be pivoted relative to the sewing material layer. This cylinder
enables setting and adjusting the clamping effect of the clamping device
to the respective sewing material layer that is to be fixed by clamping.

[0028]The invention further proposes a process for feeding a sewing
material layer from a supply device to a sewing machine, wherein the
second sewing material layer that is arranged next to, above or below the
first sewing material layer is removed from the second material roll in
the second holder of the roll receiver and fed to the sewing machine if
necessary. According to the invention, two material rolls with sewing
material layers are arranged in two holders of a roll receiver in the
supply device, and a first sewing material layer is removed from the
holder of the roll receiver and fed to the sewing machine. This enables
changing the sewing material layers as needed, without involving
considerable mounting work. Particularly short setup times can be
achieved, because the material rolls which provide the sewing material
layers according to the needs are immediately available. A change of the
sewing material layers may be provided in this connection. But it can
also be provided that merely the ceasing sewing material layer of the
first material roll is extended by the sewing material layer of the
second material roll. The invention is not limited here to the
arrangement of the sewing material layers above or below. The sewing
material layers may also overlap each other or be arranged adjacent to
each other or both.

[0029]It is proposed for the second sewing material layer to be connected
with the end of the first sewing material layer. This embodiment is
particularly suited for the continuation of sewing material layers where
the first material roll is exhausted and the sewing material layer is to
be extended by the second sewing material layer, so that the sewing
process can be continued. By this connection, the second sewing material
layer is fed to the sewing unit automatically with the processing of the
first sewing material layer. Repeated threading of the sewing material
layers is thus unnecessary.

[0030]The invention further proposes that the first sewing material layer
is separated and particularly cut into two sections substantially at
right angles to its longitudinal extension, prior to its connection with
the second sewing material layer. This embodiment is suited for changing
the sewing operation so as to continue the sewing operation using a
different sewing material layer. In this case, the first sewing material
layer is cut in such a manner that the sewing product can be finished as
intended. Immediately following is the second sewing material layer that
is intended for a further sewing product. A simple and flexible process
control can be achieved by enabling different sewing products to be
manufactured in quasi any desired manner.

[0031]Advantageously, the ends to be connected are butted up against each
other and are connected using an adhesive tape which overlaps both ends.
The adhesive tape provides for a secure connection in such a manner that
the second sewing material layer can be inserted in the sewing machine
through the first sewing material layer. An inexpensive connection is
achieved.

[0032]Moreover, it can be provided that the ends that are to be connected
with each other are arranged in an overlapping fashion one on top of the
other and are connected with each other using a connecting element
penetrating through both ends, for example a plastic thread. This
embodiment is particularly suited where the ends of the sewing material
layers to be connected with each other have different thicknesses or the
sewing material layers are not suitable for fixing an adhesive tape. A
reliable connection is obtainable also for the most different sewing
material layers.

[0033]It can be provided for the sewing material layers to be stored in
the form of material rolls in the roll receiver above each other and/or
adjacent to each other. From the production-technical view it is
beneficial to arrange the sewing material layers of different material
rolls to be connected with each other as closely adjacent to each other
as possible, thus achieving a particularly simple construction and a
simplified flow of the manufacturing process.

[0034]A further development provides that a material is stored in the
holders of a roll receiver which is substantially identical or at least
similar concerning the properties that are essential for the sewing
process. Essential properties are for example the nature of the material
such as material characteristics, loading capacity, elasticity or the
like. This embodiment is particularly suited for the manufacture of large
area sewing products.

[0035]Moreover, the sewing material layers to be connected with each other
can be fixed in their position relative to each other prior to the
connection of their ends, thus achieving a reliable connection of the
sewing material layers with each other. It can be achieved in particular
that the sewing material layers, for being stuck together, are butted up
against each other over the entire transverse extension. Moreover, a
mostly uniform overlapping portion can be obtained, which allows a
reliable connection of the two sewing material layers using a plastic
thread.

[0036]The supply device according to the invention can also be provided
for sewing material that is designed for forming a top layer. During the
manufacture of quilts or mattress panels, the sewing material is
frequently changed, so that the possibility of quickly switching between
different top layer materials arranged in a roll receiver is beneficial
precisely in this field. Preferably, these sewing material layers are
arranged in the zone just in front of the sewing unit. Here it should
also be taken into account that due to the material thickness of the top
layers, the rolls carrying the top layers usually have a smaller diameter
than the rolls carrying elastic foamed materials.

[0037]Further advantages and features will become apparent from the
following description of embodiments of the invention. Similar parts are
identified with the same reference numbers. Furthermore, concerning
identical features and functions, reference is made to the description of
the embodiment according to FIG. 2. The drawings are schematic
illustrations and merely serve to explain the following embodiment. It is
shown by:

[0039]FIG. 2 a perspective view of a sewing unit comprising a supply
device according to the invention;

[0040]FIG. 3 a schematic lateral view of the supply device according to
FIG. 2;

[0041]FIG. 4 a detail of a roll receiver of the supply device according to
FIG. 3, comprising two material rolls arranged above each other, in a
lateral view;

[0042]FIG. 5 the roll receiver according to FIG. 4, with the holder being
partly extended laterally and

[0043]FIG. 6 the roll receiver according to the FIGS. 4 and 5, with the
holder arranged in a laterally tilted position.

[0044]FIG. 1 shows a schematic lateral view of a supply device 10 for a
sewing machine 14 which comprises at least one sewing unit and with which
mattress panels are produced which in the present case consist of three
sewing material layers 16, 18, 20 which are each removed from a material
roll 24, 26, 28. In the present case, the sewing material layer 18
consists of elastic material, namely foamed material. The sewing material
layer 20 forms the top layer. The sewing material layer 16 consists of
non-elastic material.

[0045]During removal the sewing material layers 16, 18, 20 are placed on
top of each other and form the material to be sewn, which is fed to the
sewing unit via guide rollers (not further shown). Feeding of the sewing
material layers 16, 18, 20 is performed through forces acting on the
sewing material. In the sewing unit, the sewing material layers 16, 18,
20 placed on top of each other are stitched together to form the sewing
product. The sewing product is discharged via guide or deflection pulleys
(not further shown) ensuring among others that the sewing product is
tightened in the exit zone, and is supplied to secondary processing.

[0046]Above each of the material rolls 24, 26, 28 a respective replacement
roll is supported, which serves to replace the material roll arranged
below. To this end, the corresponding material roll 24, 26, 28 must first
be removed for providing space for receiving the material roll arranged
above. The latter is manually lowered to the position of the previous
material roll 24, 26, 28. After a threading action the manufacturing
process of the sewing product can be continued.

[0047]A drawback of this prior art is that if at least one of the three
sewing material layers 16, 18, 20 is to be changed or if one of the
material rolls 24, 26, 28 is exhausted, the respective material roll 24,
26, 28 must be replaced. This requires completely stopping the sewing
machine 14. The changeover requires much time, because the material rolls
must be transferred to different locations.

[0048]FIG. 2 shows a supply device 32 according to the invention, which
comprises three roll receivers 34. Each roll receiver 43 includes in the
present case two holders 42 which are arranged in pairs vertically above
each other. In the present case, the three roll receivers 34 are
horizontally arranged one behind the other, so that the respective sewing
material layers can be placed one on top of the other during their
removal from the material rolls 24, 26, 28, 36, 38, 40 arranged in the
holders 42.

[0050]The holders 42 are a component part of the roll receiver 34. The
corresponding sewing material layers can be removed from the material
rolls 24, 26, 28, 36, 38, 40 arranged in the roll receiver 34 and fed to
the sewing unit. In the present case, the sewing unit is of a type as
previously described with regard to prior art. The holders 42 of the roll
receiver 34 are arranged substantially horizontally adjacent to each
other or above each other.

[0051]In the present case, the holders 42 of the roll receiver 34 hold
material which is substantially identical or which is similar at least
concerning the properties essential for the sewing process. Accordingly,
when reaching the end of a first sewing material layer stored on the
material roll 24, 26, 28, 36, 38, 40, it may be directly switched over to
the vertically adjacent material roll 24, 26, 28, 36, 38, 40 by merely
connecting the beginning of the second sewing material layer of the
vertically adjacent material roll with the end of the first sewing
material layer.

[0053]Each holder 42 includes several rollers 48 which are rotatably
supported in the holder 42 and on which the material roll 24, 26, 28, 36,
38, 40 can be placed. A material roll which is supported on the rollers
48 can thus be displaced in the longitudinal direction of the holder 42
without considerable efforts. This embodiment not only affords a simple
exchange of the material roll 24, 26, 28, 36, 38, 40 but also the
adjustment of the material roll 24, 26, 28, 36, 38, 40 in its axial
position.

[0054]The present embodiment further provides for the supply device 32 to
comprise three roll receivers 34, each of which is designed for receiving
two material rolls 24, 26, 28, 36, 38, 40 adjacent to each other in a
vertical plane, so that the pivots 46 of the material rolls 24, 26, 28,
36, 38, 40 are aligned substantially parallel to each other. FIG. 4
illustrates the roll receiver 34 for the material rolls 16 and 24.

[0055]It is further provided that the respective upper holder 42 of the
roll receiver 34 includes a receiving assembly 50, by which a material
roll 24, 26, 40 can be moved to the respective upper holder 42 (FIGS. 4
to 6). For this purpose, the receiving assembly 50 includes a carriage 52
having a supporting surface 54 that can be applied against the material
roll 24, 26, 40. The carriage 52 can be moved between a retracted and an
extended position relative to the holder 42 and is designed for being
bent relative to the holder 42 in an end position that corresponds to the
extended position (FIGS. 5 and 6).

[0056]As shown by the FIGS. 5 and 6, the carriage 50 can be pivoted about
an axis 56, so that it can be bent in its extended end position relative
to the holder 42 in such a manner that the material roll 24, 26, 40 can
be simply removed or inserted.

[0057]In the present embodiment, the carriage 52 is L-shaped in its
longitudinal section. The carriage 52 forms a leg 58 as a supporting
structure against which the material roll 24, 26, 40 can be supported.
The material roll 24, 26, 40 can thus be replaced in an easy manner in
its extended and tilted end position.

[0058]In the present embodiment, the supporting surface 54 is formed by
several rollers 48 supported for rotation in the carriage 52. By these
rollers 48 and with the carriage 52 in its retracted position, the
material roll 24, 26, 40 can be moved to the desired axial position
without considerable efforts.

[0059]Between the carriage 52 and the receiving device 50, a linear motor
60 is coupled for moving the carriage 52 between the retracted and the
extended positions. A manual action for positioning the carriage 52 is
thus not required. Moreover, by the arrangement of the carriage 52 and
the coupling of the linear motor 60, the carriage 52 can also be tilted
to the corresponding position during its movement. Accordingly, extending
the carriage 52 simultaneously causes tilting about the axis 56, thus
enabling the carriage 52 to be moved from its material supplying position
to its roll exchanging position by only a single drive (compare FIGS. 4
to 6).

[0060]The linear motor 60 is designed as a pneumatic cylinder. But the
linear motor can also be designed as a hydraulic cylinder or as an energy
storing device using a tension spring.

[0061]The roll receiver 34 includes a supporting frame 62 on which the
holders 42 are each formed as two spaced cantilever arms 44 arranged on
the supporting frame, with a material roll 24, 26, 28, 36, 38, 40 being
supported for rotation between the cantilever arms 44. A rod forming a
pivot 46 can be inserted in the cantilever arms 44, and the rod or
cylinder is centrically passed through the material roll 24, 26, 28, 36,
38, 40.

[0062]For exchanging the material roll 24, 26, 28, 36, 38, 40, a
respective cantilever arm 44 of each holder 42 can moved relative to the
supporting frame 62, namely about an axis extending parallel to the pivot
46. This makes it possible for the respective cantilever arm to
preferably pivot away downwards, thus releasing the carriage 52 for
moving the respective material roll 24, 26, 40 in the axial direction
while the material roll 25, 26, 40 is supported on the carriage.

[0063]It can be seen in the FIGS. 2 and 3 that two holders 42 respectively
of a roll receiver 34 are associated with a connecting and guiding
assembly 64 for sewing material layers to be removed from the material
rolls 24, 26, 28, 36, 38, 40. This connecting and guiding assembly allows
fixing of a beginning or end of a sewing material layer of a material
roll currently not involved in the manufacturing process. To this end,
the connecting and guiding assembly 64 includes two mutually spaced
clamping devices by which the respective sewing material layer can be
fixed in a clamping fashion. Though not illustrated, each clamping device
includes at least one cylinder that can pivoted relative to the sewing
material layer.

[0064]The process flow for feeding a sewing material layer will be
described in the following:

[0065]Sewing material layers 14, 16, 18 are fed from the supply device 32
to a sewing machine 14 with a sewing unit for stitching the sewing
material layers together. To this end, the supply device 32 includes six
material rolls 24, 26, 28, 36, 38, 40 from which respective sewing
material layers 16, 18, 20 can be removed. The material rolls 24, 26, 28,
36, 38, 40 are arranged in pairs vertically above each other in roll
receivers 34.

[0066]As shown by FIG. 2, it is provided that the material rolls 24, 26,
28 supply sewing material layers 16, 18, 20 which are placed one on top
of the other and are fed to the sewing unit via deflection and guide
pulleys not further shown. In the present embodiment, the sewing material
layers 16, 18, 20 are stitched together to form mattress panels. Two
material rolls 24, 26, 28, 36, 38, 40 with sewing material layers 16, 18,
20 are respectively arranged in two holders 42 of a roll receiver 34. A
first sewing material layer 16, 18, 20 is removed from a holder 42 of the
roll receiver 34 and fed to the sewing machine 14.

[0067]If necessary, the sewing material layer 16, 18, 20 above or below
the first sewing material layer 16, 18, 20 can be removed from the
respective second material roll 24, 26, 28, 36, 38, 40 in the second
holder 42 of the corresponding roll receiver 34 and fed to the sewing
machine 14. For this purpose, the second sewing material layer 16, 18, 20
is connected with the end of the first sewing material layer 16, 18, 20.
For this purpose, the first sewing material layer 16, 18, 20 can be cut
on its end substantially at right angles to its longitudinal extension
for forming a straight edge, prior to its connection with the second
sewing material layer 16, 18, 20.

[0068]The ends intended for connection are butted up against each other
and are connected with each other using an adhesive tape which overlaps
both ends. Accordingly, by a continuation of the manufacturing process,
the second sewing material layer 16, 18, 20 is fed to the sewing unit
automatically through the first sewing material layer, for continuing the
sewing process. Mounting operations for exchanging material rolls 24, 26,
28, 36, 38, 40 can thus be reduced to a minimum or are performed
independently of the manufacturing process. The sewing material layers
16, 18, 20 are stored in the form of material rolls 24, 26, 28, 36, 38,
40 above each other in the roll receiver 34. Material rolls 24, 26, 28,
36, 38, 40 arranged in the holders 42 of a roll receiver 34 store
identical materials or materials which are similar at least concerning
the properties essential for the sewing process.

[0069]To achieve a good connection of the ends of the sewing material
layers 16, 18, 20 to be connected, these sewing material layers 16, 18,
20 are fixed in their position relative to each other, prior to
connecting their ends. For this purpose, the material rolls 24, 26, 28,
36, 38, 40 may be displaced in their axial position to each other.

[0070]The FIGS. 2 and 3 additionally show two material rolls 92, 94, which
are also arranged in a roll receiver, these material rolls 92, 94 storing
so-called top layer material which is placed and sewn as the uppermost
layer at the manufacture of quilts or mattress panels for example. The
manufacture of quilts and mattress panels requires frequent changes
between the top layer materials for sewing pre-planned batches of a
different design. The above-described advantages of the supply device 10
of the invention thus also apply to a supply device 10 including a roll
receiver for this top layer material according to the material rolls 92
and 94. It can be seen in the FIGS. 2 and 3 that these material rolls 92
and 94 are supported in the roll receiver 22 in direct vicinity of the
sewing machine 14, so that the top layer material is also provided in the
direct vicinity of the sewing unit. It should be noted that all the
features of the roll receiver 22 as illustrated in the supply device 10
according to FIGS. 2 and 3 and described above may be provided also with
regard to the material rolls 92 and 94 in their dedicated roll receiver
22 directly in front of the sewing machine 14. The above-described
advantages are thus also obtained in this region.

[0071]A sewing process will now be described with reference to the
following figures wherein it is shown by:

[0072]FIGS. 7 to 11 schematic process steps of a sewing process and for
cutting a thread of a lock-stitch sewing machine;

[0073]FIG. 12 a section of sewing material with the upper thread
tensioned, in a perspective view;

[0074]FIG. 13 a cutting device for cutting thread ends, in a perspective
view; and

[0075]FIG. 14 the cutting device according to FIG. 13 in a plan view.

[0076]The FIGS. 7 to 11 illustrate a process for sewing a sewing material
72 which is formed of two large area sewing material layers 16, 18 which
are connected to each other using an upper thread and a lower thread 66,
68. During this process, a needle 70 of a sewing unit (not further
illustrated) stitches together with the upper thread 70 into the sewing
material 72. The upper thread 66 is connected with the lower thread 68,
whereupon the needle 70 is removed from the sewing material 72 (FIG. 7).

[0077]For separating the lower thread 68 from the sewing material 72, a
cutting device 74 cutting the lower thread 68 is arranged below the
sewing material 72, i.e. in the region of the surface of the sewing
material 72 facing away from the needle (FIG. 8). After the lower thread
68 is cut and a free end 78 formed, the sewing material 72 is moved in
the transport direction, thus tensioning the upper thread 66 in such a
manner that the lower thread 68 which is connected with the upper thread
66 is pulled with its free end until a position above an surface 76
facing the needle 70, so that the end 78 of the lower thread 68 can be
removed in the region of this surface 76. The lower thread 68 is cut
before tensioning the upper thread 66 at the end of a sewing section. As
an alternative for moving the sewing material 72 the upper thread 66 may
also be tensioned using an independent tensioning lever not further
illustrated (FIG. 9).

[0078]The free end 78 of the lower thread 68 now protruding over the
surface 76 is cut substantially flush with the surface 76. For this
purpose a cutting device 80 is provided which will be described in the
following (FIGS. 13, 14). The lower threads 68 are for instance cut in
such a manner that their free ends 78 protruding over the surface 76 have
a length of 10 mm at maximum. The part of the lower thread 68 protruding
over the surface 76 is cut using a cutting device 80 that operates in a
two-dimensional fashion. It is provided that substantially each needle 70
has an associated cutting device.

[0079]A further embodiment provides that also the upper thread 66 is cut,
if the same rests on the surface 76, due to the transport of the sewing
material 72 between the end of a seam and the beginning of a following
seam (FIG. 10).

[0080]The upper threads 66 running on the surface 76 and not sewn up with
the sewing material 72 are substantially centrally cut using a knife 82
(FIGS. 11 and 12).

[0081]For this purpose, the knife 82 which is movable transversely to the
transport direction includes a cutting blade 84. The cutting blade 84 is
arranged inclined with respect to the surface 76 and approaches the
surface under an acute angle. Its tip can thus nip the upper thread 66,
which is cut by a sliding over the cutting blade 84. This produces thread
ends 86 of the upper thread 66. The thread ends 86 can then be cut by the
cutting device 80 together with the thread ends 78 of the lower thread 68
in one working step (FIGS. 13 and 14). If necessary, air is blown against
the thread ends of the lower threads and/or the upper threads or the
thread ends of the lower threads and/or the upper threads are aspirated,
thus providing for a reliable cutting operation.

[0082]It is provided that the lower thread 68 is pulled onto the surface
76 facing the needle 70 by means of the upper thread 66 also at the
beginning of a seam.

[0083]The cutting device 80 includes two two-dimensional cutting plates 88
which are arranged substantially parallel to each other and which can be
displaced to each other by sliding. On one side, the two cutting plates
88 include sawtooth-like appendices in the form of a sawtooth profile 90
causing a cutting effect on their adjacent edges when the cutting plates
88 are displaced against each other along the extension of the sawtooth
profile 90. The cutting device 80 is used for cutting the thread ends 78,
86 along the surface 76 of the sewing material 72. The length of the
thread ends 76, 86 can be adjusted by a corresponding selection of the
cutting plates 88.

[0084]The embodiments illustrated in the figures merely serve to explain
the invention and are not intended to limit the invention.